Twisting and plying spindle balloon control



Dec. 20, 1955 A. w. VIBBER 2,727,353

TWISTING AND FLYING SPINDLE BALLOON CONTROL Filed Nov. 9, 1954 2Sheets-Sheet l Dec. 20, 1955 A. w. VIBBER 2,7 7,

TWISTING AND FLYING SPINDLE BALLOON CONTROL Filed Nov. 9, 1954 2Sheets-Sheet 2 IN V EN TOR.

WAX/0% United States Patent TWISTIN G AND PLYING SPINDLE BALLOON CONTROLAlfred W. Vibber,'Ri'tlgewood, N. J. Application November 9, 1954,Serial No. 467,702

15 Claims. -(Cl. 57-'5 8.3)

This invention relates to the control of balloons of strandtwistingspindles, particularly spindles of the infeeding type whereinthe material in the balloon is drawn from the balloons-into-therotatingshaft or fiyer which creates and maintains the balloon. In a preferredembodiment of theinvention-it relates-to the control of the balloon ofthe'one-spindle twisting and plying system generally of the typeshownin-Clarkson-Patent No. 2,50 ,24-2,'in which two strandsare twistedtogether so as to form a two-plystrand, a first strand delivered from asupply thereof being ballooned about a let-oif strand package fromwhich'the second strand is'led.

This application is a continuation in-part of application Serial No.450,358, filed August 17, 1954.

T he present invention presents animprovement over the balloon controldevices described'in my prior applicationSerial No. 450,358in whichthe'mcans controlling the tension ofthe first strand inthe run-thereofbetween the balloon and the plying junction-is'a'balloon or loopgenerating means located on the plying shaft or fiyer. Althoughfunctioning satisfactorily :to maintain 'the balloon in the describedrange of operating diameter, the devices of my prior application aresomewhatcomplicated in construction, and require the shifting oftheballoon generating and balloon diameter detectingimeansrelative to thefiyer .upon changes inidiameterof theballoon. Although the distancesthrough which such means must move relative to the fiyer duringoperation of the device are small, in some instances such movement maythrw the plying shaft and fiyer undesirably out ofbalance, particularlywhen the shaft and fiyer rotate at high speed.

The present invention has among its objects the provision of an improvedsimplified balloontgenerating shaftcarried control for the balloon oftwisting and plying mechanism.

A further object-of the invention' res'ides in 'the vision of the aboveindicate'd'balloon eontrolling'means in which the parts ofthecontrolling means have their centers of mass fixed with respect-to'theballoon-generating shaft during operationof the'device.

A stfll further object of the invention 'lies in the provision, inapparatus whereinafirst strand isballooned about a source of supply of asecond strand to ply the two strands together, of automatic strandtens'ion'control means Wholly supported by the=twisting"ancl plyingshaft of the spindle and wherein the-strand at the exit end of theballoon interacts with a strand' snubbing member fixed with respect:tothe shaft, whereby ch-anges in the diameter of the balloon iandtthns:the degreeof its wrap-around varies the relative rate :of:a-bsorptionmf 'the two strands into the plied strand.

The above and further objects relating toieconomics of use andmanufacture tof-thedeviceiofjnvention will be more readilyapparent:upontconsiderationofthe following specification.

'My invention is clearly defined in theappended; claims. Where partsare, for clarity and conveniencqreferred 2,727,353 Patented Dec. 20,

to 'on the basis of their orientedgposition shown in the accompanyingdrawing, no limitation as 'topositioning of the entire structure is tobeimplied, since -.it 'willibe understood thatthe entire structure maybeinverted or that'it may beused in any inclined position. .Alsov inboth the description and the claims, parts at times may be identified byspccific'names for clarity and convenience, but such nomenclatureisto'be understood as having the broadest meaning consistent with'thecontext and withthe concept of my invention as distinguished from thepertinent prior art. The best form in which Ihave contemplated applyingmy invention is illustrated in the accompanying drawing forming part ofthis specification, in which:

Fig. 1 is a somewhat schematic view, partially inside elevation andpartially in vertical section, of apreferred embodiment of a one-spindlestrand plying mechanism made in accordance with the inventio Fig. 2 is aview in horizontal section through the fiyer of the spindle of Fig. 1,the section'being taken along the line 2-2 in 'Fig. 1.

Fig. 3 is a fragmentary view in vertical sectionthrongh the fiyer of thespindle of Fig. 1, the section being taken along the line 33 in Fig. 2.

Fig. 4 is an enlarged, somewhat schematic view in horizontal section ofthe portion of the fiyer at the Jeft in Fig. 2 indicating theinteractionbetween the balloon controlling means on the fiyer with .thestrand entering the fiyer from balloons of various diameters.

In the system shown in Figs. 1 and.2, the first strand, designated it),proceeds from the first let-oft" package 11 downwardly throughpositively driven strand feeding means 12 driven in synchronism with thespindle shaft 14, in a manner to ,be described, into the vballoon 15created by the fiyer .16, which constitutes -an enlarged head on shaft14. The strand 10 .ispdrawnin through the fiyer and meets the secondstrand 17 fed from the second let-oli package 19 at the point P on theaxis of the fiyer, the two strands being plied together at point P so asto emerge as the plied strandor cord 20. The cord 20 is taken up by aconventional take-up mechanism 21, preferably one such as shown inClarkson Patent No. 2,503,242, which withdraws the cord and winds iton:bobbin 22under constant dension.

Taking up now the instrumentalities which operate upon the strand 10 insuccession the firsttletvoff package 11 is preferably rotatably mounted.on 'a support 1diagrammatically shown .in Fig. 1 so as to present ,thestrand 10 opposite the feed-oil eye .into the strand feeding capstansystem 12. Means.12 is made up of atfirst multi-grooved capstan 25 andasecond -multi-grooved capstan 26 spaced therefrom, the two .capstansbeing positively geared together so as to rotate at-the same speed andin thesame direction by means of agear 27 on capstan 25, a gear 29 oncapstan 26, and the intermediate idle gear 30 meshing with -.the gearson :the capstans, all'of such mechanism being carried on fixedframe-work (not shown). Means 12, which serves to deliver the strand 10to the balloon at;essentially-constant .speed, is positively .driven insynchronism with spindle shaft .14 by the worm .3-1=on the bottom .ofshaft 14, .the worm gear .32 meshing therewith, and mounted on shaft 34,the .vertical shaft .35, .and the upper horizontal shaft 36, shafts 34,.35, and 36 being geared together, all at a 1x1 ratio, by bevel:gearszas shown, .and shaft 36 :being ,geared to .capstan .26, also bybevel gears.

The fiyer 16 is in the .nature .of :an enlarged :head or 'fiange on thetop of ithezrotatable shaft r-Shaft -14'is mounted to.rotateiinxhearings :37 in .fixetl frame parts 39 of the apparatus.:Theishaft 14 shas its iouter surface 40 between frame parts 39 crownedto engage 'rotating position, and of plying the two strands and :17together at the plying point or junction P. Let-otf package 19 issupported on a flange or platform member 41 positioned on the upper,hollow, shaft 42, the lower end of shaft 42 being journalled in theflyer 16 through the medium. of the bearing 44.- Platform 41 iseccenitrically weighted at 45 so that, when the spindle shaft 14 isdisposed at a small angle to the vertical the weight 45 willseek thelower position and thus maintain the package 19 and the shaft 42substantially non-rotating even though flyer 16 rotates at high speed.For ease of illustration the spindle shaft 1 4 is shown disposedvertically.

The shaft 42 serves also as-a support for a means 46for feeding thestrand 17 from package 19 to the plying point P at essentially constantspeed. Means 46 consists of a magnetic ball tension device 47 having anon-magnetic seat 49 positioned across the upper end of the shaft 42,the magnetic ball 50 fitting within such seat, the strand 17 progressingbetween the ball and the seat down into the shaft 42. A magnet 51positioned beneath seat member 49 maintains the ball 50 stably in itsseat. After leaving the magnetic ball tension device, the strand 17progresses into a radially outer groove on the idle upper multi-groovedfeeding capstan 52 journalled horizontally in shaft 42, and thenceproceeds downwardly to the confronting radially outer groove of thedriven lower multi-grooved capstan54. Strand 17 then travels from grooveto groove between 'capstans 52 and 54 until it reaches a central groovein driven capstan 54 from which it then travels vertically downwardly,to the plying point P.

Capstan 54 is driven in synchronism with the rotation of flyer 16 bymeans of the central hollow extension shaft 55 of the flyer, shaft 55carrying a worm 56 on its upper end. Worm 56 meshes with the hourglassworm gear 57 journalled horizontally within shaft 42 at a positionradially displaced from the axis thereof. Worm gear 57 has on its outerends the small pinions '59 which mesh with thelarger pinions 60 on theends of capstan 54. It will be apparent that rotation of the flyer 16and thus of the shaft 55 relative to the shaft 42 will positively rotatethe multi-grooved capstan 54. With the proper choice of sizes and handof the worm 56 and the worm gear 57, and the proper relative sizes ofpinions 59 and 60, the strand 17 will be fed downwardly to the plyingpoint P at the same rate that strand 10 is fed into balloon 15.

The balloon in strand 10 is created and maintained by the flyer 16 shownin Fig. 2. The strand 10 leaving the balloon 15 enters the flyer througha guiding means made up of the automatic tension control, generallydesignated 61, which functions as a balloon or loop generating means,and the generally radially directed passage 62 which conducts the strandto the plying junction P. The left-hand edge of the flyer (Fig. 2) ishorizontally slotted at 64, the slot communicating with means 61 andallowing the strand 10 to assume the various attitudes relative to theflyer from position A to position D (Fig. 4) without contacting any partof the flyer as it first enters such flyer except the first strandsnubbing member 65 of means 61. The flyer is suitably slotted at 66 onthe right-hand edge (Fig. 2) so that it runs in dynamic balance.

The strand-snubbing member 65, which is preferably made as a partseparate from the body of the flyer and from a hard material suchasCarboloy, is fixedly and non-rotatably positioned on the flyer so thatits strand receiving edge commu'nicateswith the slot 64 as shown inFigs. 2.and 3. Member 65 is provided with acentral cally in its greasesgroove 67 aligned with slot 64 to confine strand 10 vertipassage aboutmember 65. Positioned somewhat forwardly of member 65, that is, leadingit in the clockwise direction of rotation of the flyer indicated by thecurved arrow in Fig. 2 and preferably close to and staggered withrelation to member 65, as shown in Fig. 2, is the strand guiding roll 69which rotates with respect to the flyer on an axis fixed with respectthereto. Roll 69 may thus be said to be fixed with respect to the flyereven though the roll rotates on its axle 70 about its own axis; In theconstruction shown, roll 69 is journalled on the vertical axle 70 fixedto the flyer, and is provided with ball bearings 71 between the axle andthe roll body. Roll 69 has a central grooved portion 72 aligned with thegroove on member 65 and further aligned with the passage 62 leading tothe plying junction. Because the snubbing member 65 is fixedlypositioned on the flyer, and the axis of the strand guiding roll 69 isfixed with respect to the flyer, the center ofgravity of neither member65 nor roll 69 moves with respect to the flyer. The same is true of thetensioning means as a whole made up of member 65 and roll 69, that is,its center of gravity does not move with respect to the flyer.

In its passage inwardly into the flyer the strand 10 is deflected from astraight line path to the point P into a sinuous path by the loopgenerating and tension controlling means 61, the strand passing aboutthe rearwardly convex surface of member 65, leaving such surface at thepoint 74 to pass onto the roll 69 and thence through the passage 62 tothe point P. The roll 69, being journalled on substantially frictionlessbearings, causes virtually no retardation on the strand in its travelregardless of the size of the balloon from which the strand 10 isdelivered. Snubbing member 65, however, is so positioned on the fiyerand coacts with roll 69 in such manner that it imposes a variableretarding tension on the run 75 of strand 10 approaching point P. Theamount of such added tension varies with variations in the diameter ofballoon 15 so that itis relatively large when the balloon is of smalldiameter (1) and is relatively small when the balloon is of largediameter (2).

The run 75 of strand 10, therefore, is subjected to the following totaltension Tu at balloon condition (1) T(1)=Tbal1oon (1)+fadded (1 and tothe following total tension T 2 at balloon condition (2) T(2)=Tba1loon(art-leaded (a) .As we have seen,-

T balloon 2 T balloon (1) If the described means for imposing an addedretarding tension on the strand 10 were not employed, the greatertension in the'strand in the balloon as the balloon expands, plus thegreater friction imposed on it as it contacts the outer rear edge of theradial passage in the flyer due to the increased wrap-around ;of theballoon, would cause the strand 10 to approach the plying point underincreased tension. Under such condition strand 10 acts as a core atthefplying point, and more of strand 17 than strand 10 is absorbed intothe plied strand or cord 20. Thus the balloon tends to continue toexpand, since such prior ap- .paratus is not self-compensating, until itbecomes so large as to strike adjoining structures and thus to break.

The described mechanism for imposing a variable added tension on strand10 is such that the added tension falls off rapidly as the diameter ofthe balloon increases, so much so that the total tension in strand 10approaching the plying point decreases on a smooth curve from balloondiameter (1) to balloon diameter (2), in spite of the fact that thetension in the balloon proper increases as balloon diameter increases.

-' 'Ihdaction of the tension-imposing means 61 will be more readilyunderstood :by a ;eonsideration of .Fig. 4 wherein it is shown coactingwith an incoming strandfrom a balloon whose diameter varies theoperative range from a small diameter v(strandA) toa'large diameter(strand D), through t-wo.intermediate diameters (strands B and C), theballoon from whichstrand C leads being larger than that from whichstrand Bleads. This follows from the factthat as the balloondiameter'increases-the degree of wrap-around of the :balloontat thespindle in creases, so that the bottomportion oftheballoomleading to theballoon .;or,loop generating and strand tensioning means 61, makes anincreased angle zwithsthe radius of the flyeras the diameteroftheballoonincreases.

With a balloon of small diameter: (strand A) the strand has itsmaximumlength of ;contact with member 65,-such line of contactsubtending the :angle ,a from the initial contact of the strandwithmember-65 to the point 74, at which it leaves the member. Theeffective direction of the force which the strand then exerts on member65 is at a significant angle -.-with respect to the radius of the flyer,and the deviation of thestrand by member 65 is at the maximum.Accordingly,1the tension (ta) added by means 61 at such condition of theballoon-is at a maximum.

With the balloon .at a somewhat increased diameter (strand B) the strand-c,ontacts:member:65 along a line subtended by angle b,'the deviation-ofstrand Bby member 65 is less, and the eftectivedirection of the forcewhich the strand then exerts on member 6.5,iszat aysmaller. angle withrespect to the radius of-theJflyer. Consequently the tension (in) addedby means-61m: suchcondition of the balloon is less than In.

The same trends ingthe'factors contributing to the. tensioning effect ofmeans 61 onthe strand are present when it coacts with-the strands'C andD. Thus the line of contact between .strandCandmember-fiS is shorterthan it is with strand 'B, 1angle c'is smaller-than angle b, and theeffective direction of the force whichstrand .C exerts on member'65:isclosertothe radius-of the flyer than'it is with strand B.

With strand D the line of :contact between the strand and member 65 has;a:minimum length, angle dis at a minimum, and the effective.:directionof the force which strand D exerts. onmembers65 is closer totheradius of the flyer than for any ofstrandsA, B,'and C.

As a resultof.such interaction-of the strand beingpulled inwardly fromthe balloon 15 and .thetensioning means 61, the added retarding tensionon run 75 of the-strand approaching the plying pointzPis atua. maximumwhen the balloon is at its 'minimumoperative diameter, and decreases asthe balloon diameter increases,-to reacha minimum at the maximumdiameter of the balloon. vWe have seen thatthe total tension T in1runi75of strand '10.is made up of the instantaneous tensiOninIthe .strand'inthe balloon plus the tension imposed ithereon'bymeans :61. With theconstruction shown,..the added'tension imposed on the run 75 of thestranddecreases, as the balloon diameter increases, in incrementsWhichare at'least equal to those by whichthe tension of the strandin theballoon proper increases. With appropriate *factorsasuchas'diameter ofthe member .65 ,-coefficient of friction of member 65 with the strand10, and the relative .positioning of member 65 and rollert69, so .asproperly to locate the point 74 and thus to arrive:at the'desired anglesa and d, the total tension T in run 175015 the .strandmay be made todecrease as theballoon diameter increases. Such latter condition,a-decreasingztotal tensionin run 75 of strand 10, is preferred,because'of'the increased stability of the spindle.

The shape of the curve of:total tension in run 75 of strand plottedagainstballoon diametercan be changed by appropriate changes-in theshaped theconvex, strandcontacting-surfaceofzmember :65. Thus suchsurface may be made, for example, :of :either parabolic'or hyperbolicconfigurationto :yieldrtensions .added torrun .75 of strand 10 whichchange "in diflerent r manners from athat existing when member 65istcircular in cross section.

With the-apparatus of the invention, therefore, when the balloondiameter increases, :thetension in strand .10 approaching the plyingpoint decreases relative .to-the tension in strand17. Thus, the strand17; tendsto become the core, more of strand,10 thanof'strand 17 is.absorbed into the plied cord, and the :excess strand .10 in the balloonis relatively quickly absorbed into the cord to return the balloon toits optimum diameter within its operating'range. When the balloondecreases in diameter from its-optimum diarnetenxflle tension instrand10 approaching point P increases. Strand 10 thus tends to become; thecore, more of strand 17 than ofstrand ,10 is absorbed into ,the cord,the strand :10 is withdrawn from the balloon more slowly than it is fedthereinto from package 11 by means 12, and thus .the balloonris quicklyreturned to its .optimum diameter.

I claim:

1. Strand twisting. mechanism comprising: .a source .of supply of astrand, a rotatable shaft :operable to rotate aloop of the -.strand,:theshaft .having ,a generally radially disposed strand :guidingmeans'meansfor'feedingLthe strand into the loop, and means for controlling thetension in the generally radial-run of the strand, said last'named meanscomprising-.means to deflectthe generally radialrun'of the strand into asinuous path at the radially outer portion of the shaft adjacent theloop, the outer end of the sinuous'path 'being directed generallyopposite thedirection of rotation of the shaft.

2. Strandtwisting mechanism comprising: a-rotatable shaft operable torotate aloop of a strand, a source of supply ofthe strand external ofthe loop, aifirst means for feeding the strand into the loop, a secondmeans for feeding the strand out of theloop, the .shafthaving agenerally radially :disposed strand guiding means, and means forcontrolling the'tension in the generally. radial run of the strand, saidlast .named means comprising loop generating means to deflect thegenerally radial run of the strand into a sinuous path at the radiallyouter portion of the shaft adjacent the loop, the outer end of thesinuous .path being directed generally opposite the direction ,of.rotation of the shaft.

3. Mechanism for twisting together two strands .-so as to form atwo-plystrand, comprising: a source of supply of a first strand and a supportcarrying a .letoff strand package for a second zstrand, a'rotatableshaft operable to rotate a loop of the first strand about thelet-01f packageand also to ply the two .strands together, a first meansfor feedingthefirst strand intothe loop, a second means for feeding thesecond strand to :the junction where they .are plied together, and-meansfor controllingthe tension in :the run of thefirst strand approachingthe plying junction, said last named ;means comprising means on theshaftguiding the first strand generally radially inwardly to the plyingjunction, ysaid guiding means including loop generating means to deflectthe first strand into a sinuous path at the :radially outer portion ofthe shaft adjacent the loop, the outer end of'the sinuouspath beingdirected generally opposite the-direction of rotation of the shaft.

4. Strand twisting mechanism of the :infeeding type comprising: a sourceof supply or" a strand,-,a rotatable shaft operable'to rotate a loop ofthe strand, the shaft having a generally radially disposed strandreceiving passage therein, means for feeding the :Strand into :the loop,and means for controlling the tension in therun of the strand .in theradial passage in the strata-said last named means comprising means onthe-shaft guiding the strand through the radial passage'therein, saidguiding means including aloop generating means having a convexstrand'snubbing andguiding member positioned radially outwardly on -the,shaft, :and an idle guiding member the surface .of which .moves :freelywtih .the .strandwpositioned radially ,inwardlyrof .thesnnbbing :mem-

ber, said two guiding members deflecting the strand as to form a two-plystrand, comprising: a source of supply of a first strand and a supportcarrying a let-olf strand package for a second strand, a rotatable shaftoperable to rotatea loop of the first strand about the let-off packageand also to ply the two strands together,

a firstrneans for feeding the first strand into the loop, a second meansfor feeding the second strand to the junction where they are pliedtogether, and means for controlling the tension in the run of the firststrand approaching the plying junction, said last named means comprisingmeans on the shaft guiding the first strand generally radially of theshaft to the plying junction, said guiding means including a loopgenerating means having a strand snubbing and guiding member positionedradially outwardly on the shaft, and an idle guiding member the surfaceof which moves freely with the strand positioned radially inwardly ofthe snubbing member, said two guiding members deflecting the strand intoa sinuous path at the radially outer portion of the shaft adjacent theloop, the outer end of the sinuous path being directed generallyopposite the direction of rotation of the shaft.

6. Mechanism for twisting together two strands so as to form a two-plystrand, comprising: a source of supply of a first strand and a supportcarrying a let-off strand package for a second strand, a rotatable shaftoperable to rotate'a loop of the first strand about the let-off packageand also to ply the two strands together, a first means for feeding thefirst strand into the loop, a second means for feeding the second strandto the junction where they are plied together, and means for controllingthe tension in the run of the first strand approaching the plyingjunction, said last named means comprising means on the shaft guidingthe first strand generally radially inwardly of the shaft to the plyingjunction, said guiding means including-a loop generating means having aconvex strand snubbing and guiding member positioned radially outwardlyon the shaft,

and an idle guiding member the surface of which moves freely with thestrand positioned radially inwardly of the snubbing member, said twoguiding members deflecting the strand into a sinuous path at theradiallyouter portion of the shaft adjacent the loop, the outer end of thesinuous path being directed generally opposite the direction of rotationof the shaft.

7. Mechanism for twisting together two strands so as to form a two-plystrand, comprising: a source of supply of a first strand and a supportcarrying a let-off strand package for a second strand, a rotatable shaftoperable to rotate a loop of the first strand about the let-off packageand also to ply the two strands together, a first means for feeding thefirst strand into the loop, a second means for feeding the second strandto the junction where they are plied together, and means for controllingthe tension in the run of, the first strand-approaching the plyingjunction, said last named means comprising means on the shaft guidingthe first strandv generally radially inwardly of the shaft to the plyingjunction, said guiding means including a loop generating means having astrand snubv bing member with a convex surface facing in the directionopposite the direction of rotation of the shaft, and fixedly positionedradially outwardly on the shaft, and an idle guiding member the surfaceof which moves freely with the strand fixedly positioned radiallyinwardly of the snubbing member, said two guiding members deflecting thestrand into a sinuous path which passes over the said convex surface ofthe snubbing member and over the idle guiding member on the side thereofwhich leads during rotation of the shaft, the first strand passingdirectly from the loop into contact with the snubbing member. I r

8. Mechanism for twisting togethertwo strands so as V to form a two-plystrand, comprising: a source of supply of a first strand and a supportcarrying a let-offstrand package for a second strand, a rotatable shaftoperable to rotate a loop of the first strand about the let-off packageand also to ply the two strands together, a first means for feeding thefirst strand into the loop, a second means for feeding the second strandto the junction where they are plied together, and'means for controllingthe tension inthe run of the'first strand approaching the plyingjunction, said last named means comprising means on the shaft guidingthe first strand generally radially inwardly of the shaft to the plyingjunction, said guiding means including a loop generating means-having astrand snubbing member with a convex surface facing in the directionopposite the direction of rotation of the shaft, and fixedly positionedradially outwardly; on the shaft, and an idle guiding member the surfaceof which moves freely with the strand fixedly positioned radiallyinwardly of the snubbing member, said two guiding members deflecting thestrand into a sinuous path which passes over the said convex surface ofthe snubbing member and over the idle guiding member on the side thereofwhich leads during rotation of the shaft,-the first strand passingdirectly from the loop into contact with the snubbing member, the lengthof the zone of contact between the snubbing member and the stranddecreasing as the degree of wrap-around of the loop increases.

9. Mechanism for twisting together two strands so as to form a two-plystrand, comprising: a source of supply of a first strand and a "supportcarrying a let-off strand package for a second strand, a rotatable shaftoperable to rotate a loop of the first strand about the let-off packageand also to ply the two strands together, a first substantially constantspeed :means for feeding the first strand into the loop, a secondsubstantially constant speed means for feeding the second strand to thejunction where they are plied together, and means for controlling thetension in the run of the first strand approaching the plying junction,said last named means comprising means on the shaft guiding the firststrand to the plying junction, said guiding means including means todeflect the strand into a sinuous path at the radially outerportion ofthe shaft adjacent the loop, the outer end of the sinuous path beingdirected generally opposite the direction of rotation of the shaft. Y j

10. Strand twisting mechanism comprising: a source of supply of astrand, a rotatable shaft operable to rotate a loop of the strand, theshaft having a generally radially disposed strand receiving passagetherein, a first substantially constant speed means for feeding thestrand into the loop, and means' for controlling the tension in the runof the first strand in the radial passage in the shaft, said last namedmeans comprisingmeans on the shaft guiding the first strand through theradial passage therein, said guiding means including loop generatingmeans having means to deflect the strand into a sinuous path at theradially outer portion of the shaft adjacent the loop, the outer end ofthesinuous path. being directed generally opposite the direction ofrotation of the shaft.

11. Mechanism for twisting together two strands so as to form a two-plystrand, comprising: a source of supply of a first strand and a supportcarrying a let-off strand package for a second strand, a rotatable shaftoperable to rotate a loop of the first strand about the let-off packageand also to ply the two strands. together, a first substantiallyconstant speed means for feeding thefirst strand into the loop, a secondsubstantially constant speed means for feeding the second strand to thejunction where they are plied together, and means for controlling thetension in the run of the first strand approaching the plying junction,said last named means comprising means on the shaft guiding the firststrand generally radially of the shaft to the plying junction, saidguiding means including a loop generating means having a convex strandsnubbing and guiding member positioned radially outwardly on the shaft,and an idle guiding member the surface of which moves freely with thestrand positioned radially inwardly of the snubbing member, said twoguiding members deflecting the strand into a sinuous path at theradially outer portion of the shaft adjacent the loop, the outer end ofthe sinuous path being directed generally opposite the direction ofrotation of the shaft.

12. Mechanism for twisting together two strands so as to form a two-plystrand, comprising: a source of supply of a first strand and a supportcarrying a let-off strand package for a second strand, a rotatable shaftoperable to rotate a loop of the first strand about the let-off packageand also to ply the two strands together, a first substantially constantspeed means for feeding the first strand into the loop, a secondsubstantially constant speed means for feeding the second strand to thejunction where they are plied together, and means for controlling thetension in the run of the first strand aproaching the plying junction,said last named means comprising means on the shaft guiding the firststrand generally radially of the shaft to the plying junction, saidguiding means including a loop generating means having a strand snubbingmember with a convex surface facing opposite the direction of rotationof the shaft, and fixedly positioned radially outwardly on the shaft,and an idle guiding member, the surface of which moves freely with thestrand, fixedly positioned radially inwardly of the snubbing member,said two guiding members deflecting the strand into a sinuous path whichpasses over the said convex surface of the snubbing member and over theidle guiding member on the side thereof which leads during rotation ofthe shaft, the first strand passing directly from the loop into contactwith the snubbing member.

13. Mechanism for twisting together two strands so as to form a two plystrand, comprising: a source of supply of a first strand and a supportcarrying a let-off strand package for a second strand, a rotatable shaftoperable to rotate a loop of the first strand about the let-off packageand also to ply the two strands together, a first substantially constantspeed means for feeding the first strand into the loop, a secondsubstantially constant speed means for feeding the second strand to thejunction where they are plied together, and means for controlling thetension in the run of the first strand approaching the plying junction,said last named means comprising means on the shaft guiding the firststrand generaly radially of the shaft to the plying junction, saidguiding means including a loop generating means having a strand snubbingmember with a convex surface facing opposite the direction of rotationof the shaft, and fixedly positioned radially outwardly on the shaft,and an idle guiding member, in the form of a roll the surface of whichmoves freely with the strand, fixedly positioned radially inwardly ofthe snubbing member, said two guiding members deflecting the strand intoa sinuous path which passes over the said convex surface of the snubbingmember and over the idle guiding member on the side thereof which leadsduring rotation of the shaft, the first strand passing directly from theloop into contact with the snubbing member, the length of the zone ofcontact between the snubbing member and the strand decreasing as thedegree of wrap-around of the loop increases.

14. A strand twisting mechanism, comprising: a driven shaft for rotatinga loop of a strand, means for feeding the strand into the loop, meansfor Withdrawing the strand from the loop in a run extending at leastgenerally radially of the shaft, and loop generating means fixed withrespect to the shaft, said loop generating means including means fixedwith respect to the loop generating means for imposing a first retardingtension on the generally radial run of the strand when the loop is of asmall size and for imposing a progressively smaller retarding tension onsuch run as the loop increases in size.

15. A strand twisting mechanism, comprising: a driven shaft for rotatinga free-flying loop of a strand, means for feeding the strand into theloop, means for withdrawing the strand from the loop in a run extendingat least generally radially into the shaft, loop generating meanslocated radially outwardly of the shaft and fixed with respect to theshaft, said loop generating means including means deflecting andsnubbing the outer end of the generally radial run of the strand so asto impose thereon a first retarding tension when the loop is of a smalldiameter and to impose a progressively smaller retarding tension thereonas the loop increases in diameter.

References Cited in-the file of this patent UNITED STATES PATENTS1,031,367 Norman July 2, 1912 2,074,096 Suydam Mar. 16, 1937 2,503,242Clarkson Apr. 11, 1950 2,550,136 Clarkson Apr. 24, 1951

